US9064976B1 - Modeling charge distribution on FinFET sidewalls - Google Patents
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- US9064976B1 US9064976B1 US14/557,578 US201414557578A US9064976B1 US 9064976 B1 US9064976 B1 US 9064976B1 US 201414557578 A US201414557578 A US 201414557578A US 9064976 B1 US9064976 B1 US 9064976B1
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- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
- H01L21/77—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate
- H01L21/78—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices
- H01L21/82—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices to produce devices, e.g. integrated circuits, each consisting of a plurality of components
- H01L21/84—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices to produce devices, e.g. integrated circuits, each consisting of a plurality of components the substrate being other than a semiconductor body, e.g. being an insulating body
- H01L21/845—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices to produce devices, e.g. integrated circuits, each consisting of a plurality of components the substrate being other than a semiconductor body, e.g. being an insulating body including field-effect transistors with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
- H01L29/76—Unipolar devices, e.g. field effect transistors
- H01L29/772—Field effect transistors
- H01L29/78—Field effect transistors with field effect produced by an insulated gate
- H01L29/785—Field effect transistors with field effect produced by an insulated gate having a channel with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
- H01L29/7853—Field effect transistors with field effect produced by an insulated gate having a channel with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET the body having a non-rectangular crossection
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/02—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers
- H01L27/12—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers the substrate being other than a semiconductor body, e.g. an insulating body
- H01L27/1203—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers the substrate being other than a semiconductor body, e.g. an insulating body the substrate comprising an insulating body on a semiconductor body, e.g. SOI
Definitions
- the present invention relates generally to the field of semiconductor manufacturing, and more particularly to a method for estimating variability in device performance.
- CMOS Complementary metal-oxide semiconductor
- dimensional scaling increases the importance of the local variation in charge at the semi-conductor-oxide interface.
- Statistical variation in charge is inversely proportional to the square root of the device gate area. Consequently, scaling results in device electrical performance (e.g., linear current, effective current, and threshold voltage) being more strongly affected by statistical fluctuations in the spatial variation of charge at the semi-conductor-oxide interface.
- Conventionally identified and/or modeled sources of charge variation include: (i) random dopant fluctuation (RDF); (ii) dimensional variations (e.g., device length, device width, local channel length, fin width, fin height, and fin angle); (iii) work function variation (e.g. gate work function); (iv) granularity (e.g. metal grain granularity); and (v) oxygen vacancy concentration variation.
- RDF random dopant fluctuation
- dimensional variations e.g., device length, device width, local channel length, fin width, fin height, and fin angle
- work function variation e.g. gate work function
- granularity e.g. metal grain granularity
- oxygen vacancy concentration variation oxygen vacancy concentration variation.
- the method includes: inputting structure parameters and simulation parameters for a FinFET structure; identifying a semiconductor-oxide interface in the structure, the interface including a plurality of atomic steps and a plurality of trapped charges; distributing charges at the interface; and performing device simulations and current-voltage analysis upon generating all samples of given number of devices.
- FIG. 1 illustrates schematics of an ideal rectilinear FinFET, idealized tapered FinFET, and realistic FinFET with dimensional variations subject to variations in charge;
- FIG. 2 illustrates a 3D view of an STM image of a stepped Si(111) surface in which each step of this atomic staircase is about 0.3 nm high;
- FIG. 3 shows a flow chart for modeling charge distribution associated with steps on the sidewalls of a FinFET according to an embodiment of the present invention
- FIG. 4 depicts a resulting structure for simulation where the number of horizontal charge strips placed on the fin sidewall is a function of the average fin taper angle according to an embodiment of the present invention
- FIG. 5 shows an example for the placement of vertical strips of charge associated with waviness from source to drain according to an embodiment of the present invention
- FIG. 6 depicts an alternate representation of charge stripes comprising of horizontal strips from the taper angle and vertical charge strips arising from source-drain lattice irregularities according to an embodiment of the present invention
- FIG. 7 shows calculated threshold voltages (V t ) resulting from horizontal charge strips placed on the fin sidewall for various fin angles at different oxide thickness according to an embodiment of the presentation
- FIG. 8 shows calculated threshold voltages (V t ) resulting from vertical charge strips placed from drain to source according to an embodiment of the presentation
- FIG. 9 shows threshold voltage standard deviation simulated for different oxide thickness using horizontal charge strips on the fin sidewall according to an embodiment of the presentation.
- FIG. 10 shows a Pelgrom plot for undoped FinFETs for thin (1.2 nm) and thick (3.2 nm) dielectrics.
- Mismatch plays a key role in low-voltage SRAM (static random access memory) functionality. Mismatch is often characterized in terms of a parameter called “AVT,” also shown as ⁇ V t , which is the slope of transistor matching (the standard deviation of the difference in threshold voltages between two nearby, nominally identical transistors) relative to the square root of the transistor area. Not all phenomena truly scale with the square root of the transistor area, but this metric is familiar and provides for easy, albeit superficial, benchmarking. Conventionally identified and modeled sources of device variability, as aforementioned, however, do not account for the total variation observed experimentally, as shown in Table 1 comparing conventionally calculated AVT 150 with experimentally measured AVT 160 for an n-type FET (nFET).
- nFET n-type FET
- the sources modeled in Table 1 include: (i) random dopant fluctuation (RDF); (ii) metal grain granularity (MGG); (iii) oxygen vacancy (O-V); (iv) gate length variation (GLV); (v) fin width variation (FWV); (vi) fin height variation (FHV); and (vii) fin angle variation (FAV).
- RDF random dopant fluctuation
- MSG metal grain granularity
- O-V oxygen vacancy
- GLV gate length variation
- FWV fin width variation
- FHV fin height variation
- FAV fin angle variation
- Some embodiments of the present invention recognize additional sources of charge variation.
- An exemplary method of modeling charge distribution associated with steps on FinFET sidewalls for estimating variability in device performance is discussed below.
- the additional sources of local charge variation at semiconductor-oxide interfaces include: (i) interface traps; and (ii) unpassivated bonds.
- Interface traps present at the points of disturbance of the silicon lattice in tapered and wavering fins contribute to transistor mismatch.
- Unpassivated bonds result from the steps on FinFET sidewalls. These steps are generated as a result of: (i) miscut surfaces; (ii) curved surfaces (e.g., nanowires and nanotubes); and/or (iii) lithography processes.
- the AVT calculation in Table 3 includes contributions from both conventional sources and from the additional sources, presented herein, specifically, fin miscut and/or misregistration. Table 3 presents the AVT 170 where the additional sources are accounted for.
- the contribution from the variation in charge associated with the additional sources is larger than any single other contributions associated with the conventionally identified sources.
- the “misregistration” is associated with variation in placement (e.g., in a sidewall image transfer process or a lithography process).
- Comparison between Tables 1 and 3 shows that AVT (1.52) calculated by including the additional identified sources is in an excellent agreement with the experimentally measured AVT value (1.50).
- FIG. 1 schematically shows ideal FinFET 102 (untapered and straight) compared with ideal tapered FinFET 104 having some taper in its profile. While for electrostatic analysis the deviations from orthogonal is considered in a continuum sense, in reality, tapered FinFET 106 ( FIG. 1 ) includes jogs (such as jog 108 ) in the lattice on an atomic level which disrupts the regularity of the lattice.
- jogs such as jog 108
- FIG. 2 shows a perspective view of an STM (scanning tunneling microscope) image of stepped Si(111) surface 202 .
- Each step (e.g. step 204 ) of this atomic staircase is roughly 0.3 nm high.
- FIG. 2 illustrates how such atomic steps appear on planar silicon, which is cut at an angle to the lattice.
- the miscut angle for surface 202 is about 1° off the crystallographic direction (100) and the vertical axis is thus stretched by a factor of about 15 to clearly show the atomic steps.
- Unpassivated bonds e.g., broken or highly strained bonds
- charge variations associated with steps on the FinFET sidewalls is modeled in the context of transistor matching by using a technology computer-aided design (TCAD) tool.
- TCAD refers to the use of computer simulations to develop and optimize semiconductor processing technologies and devices.
- FIELDAY a proprietary IBM TCAD tool for calculating electrical behavior
- IBM TCAD IBM TCAD tool for calculating electrical behavior
- IBM IBM TCAD tool for calculating electrical behavior
- FIELDAY solves a system of fully-coupled partial differential equations governing electrostatics, current transport, carrier and lattice energy in a typical semiconductor device, for example, bipolar junction transistor (BJT) and FETs, in hydrodynamic simulation framework.
- BJT bipolar junction transistor
- FET field-effect transistor
- the partial-differential equations are discretized to obtain a set of nonlinear equations using control volume method.
- a 3-D mesh consisting of a mixture of prisms and tetrahedral is used.
- a fully-coupled Newton scheme is used to produce a large sparse linear system of equations from the set of nonlinear equations.
- a sparse matrix linear solver program is used to obtain the solution of the linear system of equations.
- FIG. 3 shows flowchart 100 depicting a first method for modeling charge distribution associated with steps on FinFET sidewalls according to the present invention.
- the structure information may include, but is not limited to: (i) fin width; (ii) fin height; (iii) fin angle; (iv) fin taper profile; (v) gate lengths; (vi) equivalent gate dielectric thickness (e.g. oxide thickness); (vii) source/drain doping profile; (viii) channel doping profile; (ix) channel length; (x) source/drain extension; (xi) buried oxide (BOX) thickness; (xii) sub-fin punchthrough-stopper doping profile; and/or (xiii) gate location relative to extension depth.
- the simulation parameter set may include, but is not limited to: (i) material electronic properties; (ii) lumped source/drain series resistance; (iii) doping gradient; (iv) density-of-states carrier effective mass; (v) carrier saturation velocity; and/or (vi) metal gate work function.
- the input device structure information comes from process simulation steps using tools like Sentaurus Process or Taurus TSUPREM-4 or through CAD operations and process emulation steps with the aid of tools like Sentaurus Structure Editor.
- Sentaurus Process may be subject to trademark rights in various jurisdictions throughout the world and are used here only in reference to the products or services properly denominated by the marks to the extent that such trademark rights may exist.
- the spatial mesh consisting of a mixture of prisms and tetrahedral may also be generated using those tools.
- step S 104 semiconductor/oxide interface in the FinFET structure is identified.
- geometric information is obtained from the structure including: (i) node; (ii) element; and/or (iii) contact, to identify different interfaces.
- a semiconductor/oxide interface in the structure is identified where charges distribute on the interface between channel and gate dielectric layer.
- step S 106 charge distribution at the semiconductor/oxide interface is simulated.
- steps that are comparable to atomic dimensions.
- there remain unpassivated dangling bonds that can lead to a significant amount of charge being present along these steps on the fin sidewall.
- the effect of steps is simulated by defining strips of charge on the silicon/oxide interface. Charge is distributed along the randomly appearing steps on the sidewall surface, which can be done by employing, for example, a random number generator, auto-correlation functions, or any other function that can be applied to simulate the distribution of steps.
- the number of steps along the fin height is determined by: (i) the taper angle; and (ii) the dimensions of the fin.
- the placement of charge strips, however, can be random.
- FIG. 4 depicts resulting structure 400 (including source 406 and drain 408 ) for simulation where the number of horizontal charge strips 402 placed on fin sidewall 404 is a function of the average fin taper angle.
- the number and placement of steps along source-to-drain dimension on the fin sidewall is a consequence of the fabrication steps, whether the fin dimension is determined by lithography or by a sidewall image transfer process.
- FIG. 5 illustrates an exemplary placement 500 (including source 506 , fin sidewall 504 , and drain 508 ) of strips of charge associated with waviness from source to drain, in which vertical charge strip 501 is placed at source extension, vertical charge strip 502 is placed at gate, and vertical charge strip 503 is placed at drain extension.
- charge strips such as strips 501 , 502 , 503 , and 402 , on the fin sidewalls have a density indicative of the fraction of unpassivated bonds.
- the charge density is determined from ab-initio calculations.
- the placement of steps is uniform spatially and correlated on each sidewall of the fin.
- each sidewall of the fin is treated independently.
- vertical and horizontal strips are treated individually.
- a more sophisticated approach based on random numbers (e.g., by a random number generator) and/or auto-correlation functions is adopted to capture the full ensemble of devices incorporating both phenomena together (i.e., vertical strips and horizontal strips), as illustrated in FIG. 6 .
- FIG. 6 depicts a second embodiment 600 of the present invention.
- Charge strips include both vertical strips 602 placed according to the fin taper angle, and horizontal strips 601 placed according to source-drain lattice irregularities.
- Embodiment 600 further includes source 606 , fin sidewall 604 , and drain 608 .
- Processing proceeds to step S 108 , where a decision is made as to whether to include more device samples for simulation. Generating multiple samples for charge distribution allows the calculation of statistics for device performance metrics.
- step S 110 device simulations and current-voltage (I-V) analysis is performed on samples of the given number of devices obtained from step S 106 .
- I-V current-voltage
- n and P are electron and hole concentrations, respectively, ⁇ is electrostatic potential, ⁇ is dielectric constant of the material, R n and R p are the net generation rate of electron and holes, q is the electronic charge, N is net impurity density, and J n , J p are current densities.
- Charges specified on the semi-conductor/oxide interface go into the Poisson equation (equation (1)) that is solved for the electrostatic potential distribution in device and solved self-consistently with carrier transport equations.
- exemplary calculated threshold voltages are shown in chart 700 according to an embodiment of the present invention.
- the threshold voltage results from horizontal charge strips that are placed on the fin sidewall for various fin angles at different gate oxide thicknesses (t ox ).
- the number of steps represent the fin angle, i.e., the more steps on the fin sidewall, the larger the tapering angle of the fin.
- the gate oxide thicknesses (t ox ) are 1.2 nm and 3.1 nm, respectively.
- the calculated threshold voltages are plotted as a function of assumed charge density (i.e., surface charge density: #/cm 2 ) in the strips for: (i) several angles; and (ii) the two gate dielectric oxide thicknesses.
- the surface charge density indicates the fraction of unpassivated bonds at the steps. As seen from FIG. 7 , the more steps or the thicker the oxide results in a further shift of the threshold voltage. In this example, no specific implication as to the sign of the threshold voltage shift is intended.
- the sign of the threshold voltage shift depends on the nature of the unpassivated, or strained, bond at the lattice interruption. Further, the assumed charge sign is positive, but that assumption is not relevant to a statistical calculation.
- exemplary calculated threshold voltages are shown in chart 800 according to an embodiment of the present invention.
- the threshold voltage results from vertical charge strips placed along drain-to-source for a specific fin angle (e.g., 5 steps on the fin sidewall at a specified gate oxide thickness (e.g., 1.2 nm)).
- the calculated threshold voltages are plotted as a function of assumed charge density (i.e., surface charge density: #/cm 2 ) in the strips and locations of a single lattice irregularity (i.e, step/strip) along the source to the drain.
- the surface charge density indicates the fraction of unpassivated bonds at the steps.
- the locations of strips placed along the source to the drain are designated as: center, source end, source halfway, drain end, and drain halfway, respectively.
- the largest impact on threshold voltage is from the charge strip placed on the gate (e.g., center position). Charges placed outside of the gate have no impact on the threshold voltage (e.g., source end or drain end). While a lattice discontinuity located within the active channel is quite important, as expected, the response (e.g., threshold voltage) depends on the location of the charge in the channel (e.g., source halfway or drain halfway). In this example, no specific implication as to the sign of the threshold voltage shift is intended. The sign of the threshold voltage shift depends on the nature of the unpassivated, or strained, bond at the lattice interruption. Further, the assumed charge sign is positive, but that assumption is not relevant to a statistical calculation.
- exemplary threshold voltage standard deviations are shown in chart 900 according to an embodiment of the present invention.
- the standard deviation is based on simulation of different gate oxide thicknesses using horizontal charge strips on a fin sidewall. Statistics are applied to the fin taper angle (i.e., number of strips and placement of strips) to calculate the resultant mismatch ( ⁇ Vt ) from this mechanism (i.e., fin angle variation) for a +/ ⁇ 3 degree deviation in fin angle.
- the calculated threshold voltage standard deviation is plotted as a function of assumed charge density (i.e., surface charge density: #/cm 2 ) in the strips placed on the fin sidewall for two gate oxide thicknesses (i.e., 1.2 nm and 3.1 nm).
- the surface charge density indicates the fraction of unpassivated bonds at the steps. For example, the 99%, 90%, and 0% points in chart 900 represent the passivation percentage of unpassivated bonds at steps. In this example, no specific implication as to the sign of the threshold voltage shift is intended.
- the sign of the threshold voltage depends on the nature of the unpassivated or strained bond at the lattice interruption. Further, the assumed charge sign is positive, but that assumption is not relevant to a statistical calculation.
- the simulated results shown in FIGS. 7 , 8 , and 9 are compared with experimentally measured FinFET hardware data.
- Pelgrom plot 1000 illustrates an exemplary threshold voltage matching data ( ⁇ V t , as in saturated) experimentally measured for undoped FinFETs for different gate oxide thicknesses (i.e., 1.2 nm and 3.2 nm) according to the present invention.
- the FinFETs for which hardware matching data is obtained are undoped SOI (silicon-on-insulator) nFETs (n-type FET).
- the standard deviation of the difference in threshold voltage between two nearby, nominally identical transistors ( ⁇ V t , as in saturated), is plotted relative to the square root of the transistor area (1/sqrt(A)).
- Mismatch is characterized in terms of the parameter AVT, which is the slope of transistor matching data plot.
- Some embodiments of the present invention may include one, or more, of the following features, characteristics and/or advantages: (i) Interface traps present at the points of disturbance of the silicon lattice in tapered and wavering fins are shown to contribute to transistor mismatch; (ii) unpassivated bonds due to steps on miscut surfaces, curved surfaces or lithography processes contribute to transistor mismatch; (iii) misregistration along the source/drain axis contributes to transistor mismatch; (iv) the consideration of charge variation mechanisms identified in the present invention improves the quantitative understanding of matching in undoped thin- and thick-dielectric SOI FinFETs; (v) a methodology of statistically representing the charge variation associated with variation sources identified in the present invention is described in a TCAD framework to show that the results of these calculations represent a plausible and numerically reasonable explanation for empirically observed matching and threshold voltage variation; (vi) the nominal threshold voltage is shown to be a function of fin taper angle; (vii) control of the fin profile is critical to threshold voltage control and matching; and/or
- Present invention should not be taken as an absolute indication that the subject matter described by the term “present invention” is covered by either the claims as they are filed, or by the claims that may eventually issue after patent prosecution; while the term “present invention” is used to help the reader to get a general feel for which disclosures herein that are believed as maybe being new, this understanding, as indicated by use of the term “present invention,” is tentative and provisional and subject to change over the course of patent prosecution as relevant information is developed and as the claims are potentially amended.
- Embodiment see definition of “present invention” above—similar cautions apply to the term “embodiment.”
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Abstract
Description
TABLE 1 |
Conventional AVT (150) and experimental |
AVT (160) for a given n-type FET. |
RDF | MGG | O-V | GLV | | FHV | FAV | 150 | 160 | ||
nFET | 10.00 | 11.20 | 12.00 | 7.00 | 4.80 | 2.20 | 8.70 | 1.05 | 1.50 | |
TABLE 2 |
Brief list of published fully depleted matching data. |
AVT (σΔVt) | TYPE | ||
1.27 | FDSOI | ||
1.30 | FDSOI | ||
1.50 | FinFET | ||
1.75 | FinFET Amorphous Gate | ||
Arbitrary Units Only | Bulk FinFET | ||
1.23 | SOI FinFET | ||
1.20 | SOI FinFET | ||
TABLE 3 |
Improved AVT calculation (170) taking into account additional |
source(s) of charge variation for a given n-type FET. |
ADDITIONAL | |||||||||
RDF | MGG | O-V | GLV | FWV | FHV | FAV | SOURCE(S) | 170 | |
nFET | 10.00 | 11.20 | 12.00 | 7.00 | 4.80 | 2.20 | 8.70 | 24.00 | 1.52 |
∇·∈∇φ+q(p−n+N)=0 (1)
In above equations, n and P are electron and hole concentrations, respectively, φ is electrostatic potential, ∈ is dielectric constant of the material, Rn and Rp are the net generation rate of electron and holes, q is the electronic charge, N is net impurity density, and Jn, Jp are current densities. Charges specified on the semi-conductor/oxide interface go into the Poisson equation (equation (1)) that is solved for the electrostatic potential distribution in device and solved self-consistently with carrier transport equations.
TABLE 4 |
Numerical assessment of mismatching data and corresponding |
empirical results for both a thin oxide and a thick oxide. |
ADDITIONAL | ||||||||||
RDF | MGG | O-V | GLV | FWV | FHV | FAV | SOURCE(S) | 170 | 160 | |
THICK | 15.40 | 7.10 | 12.80 | 0.60 | 1.33 | 1.83 | 2.47 | 20.30 | 2.08 | 1.8-2 |
THIN | 10.70 | 14.50 | 12.80 | 7.00 | 4.80 | 2.20 | 8.70 | 12.00 | 1.18 | 1.20 |
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Cited By (2)
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US9570550B1 (en) | 2016-01-05 | 2017-02-14 | International Business Machines Corporation | Stacked nanowire semiconductor device |
CN110957365A (en) * | 2018-09-27 | 2020-04-03 | 台湾积体电路制造股份有限公司 | Semiconductor structure and semiconductor circuit |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6864520B2 (en) | 2002-04-04 | 2005-03-08 | International Business Machines Corporation | Germanium field effect transistor and method of fabricating the same |
US8212336B2 (en) | 2008-09-15 | 2012-07-03 | Acorn Technologies, Inc. | Field effect transistor source or drain with a multi-facet surface |
US8268729B2 (en) | 2008-08-21 | 2012-09-18 | International Business Machines Corporation | Smooth and vertical semiconductor fin structure |
US8354721B2 (en) | 2010-02-11 | 2013-01-15 | Shanghai Institute Of Microsystem And Information Technology, Chinese Academy Of Sciences | Gate-all-around CMOSFET devices |
US8513102B2 (en) * | 2010-11-08 | 2013-08-20 | Leonard Forbes | Reduction of random telegraph signal (RTS) and 1/f noise in silicon MOS devices, circuits, and sensors |
US8575009B2 (en) | 2012-03-08 | 2013-11-05 | International Business Machines Corporation | Two-step hydrogen annealing process for creating uniform non-planar semiconductor devices at aggressive pitch |
-
2014
- 2014-12-02 US US14/557,578 patent/US9064976B1/en not_active Expired - Fee Related
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6864520B2 (en) | 2002-04-04 | 2005-03-08 | International Business Machines Corporation | Germanium field effect transistor and method of fabricating the same |
US8268729B2 (en) | 2008-08-21 | 2012-09-18 | International Business Machines Corporation | Smooth and vertical semiconductor fin structure |
US8212336B2 (en) | 2008-09-15 | 2012-07-03 | Acorn Technologies, Inc. | Field effect transistor source or drain with a multi-facet surface |
US8354721B2 (en) | 2010-02-11 | 2013-01-15 | Shanghai Institute Of Microsystem And Information Technology, Chinese Academy Of Sciences | Gate-all-around CMOSFET devices |
US8513102B2 (en) * | 2010-11-08 | 2013-08-20 | Leonard Forbes | Reduction of random telegraph signal (RTS) and 1/f noise in silicon MOS devices, circuits, and sensors |
US8575009B2 (en) | 2012-03-08 | 2013-11-05 | International Business Machines Corporation | Two-step hydrogen annealing process for creating uniform non-planar semiconductor devices at aggressive pitch |
Non-Patent Citations (5)
Title |
---|
Chung et al., "The effects of Low-Angle Off-Axis Substrate Orientation on MOSFET Performance and Reliability", IEEE Transactions on Electron Devices, vol. 38, No. 3, Mar. 1991, pp. 627-633, © 1991 IEEE. |
Einstein, "Using the Wigner-Ibach surmise to analyze terrace-width distributions: history, user's guide, and advances", Applied Physics A, Materials Science & Processing, vol. 87, No. 3, 2007, pp. 375-384, Published online: Feb. 28, 2007, © Springer-Verlag 2007. |
Jin et al., "Modeling of Surface-Roughness Scattering in Ultrathin-Body SOI MOSFETs", IEEE Transactions on Electron Devices, vol. 54, No. 9, Sep. 2007, pp. 2191-2203, © 2007 IEEE. |
Patel et al., "Gate Line Edge Roughness Model for Estimation of FinFET Performance Variability", IEEE Transactions on Electron Devices, vol. 56, No. 12, Dec. 2009, pp. 3055-3063, © 2009 IEEE. |
Sato et al., "Effects of corner angle of trapezoidal and triangular channel cross-sections on electrical performance of silicon nanowire field-effect transistors with semi gate-around structure," Solid-State Electronics, vols. 65-66, 2011, pp. 2-8, © 2011 Elsevier Ltd, All rights reserved. |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9570550B1 (en) | 2016-01-05 | 2017-02-14 | International Business Machines Corporation | Stacked nanowire semiconductor device |
CN110957365A (en) * | 2018-09-27 | 2020-04-03 | 台湾积体电路制造股份有限公司 | Semiconductor structure and semiconductor circuit |
CN110957365B (en) * | 2018-09-27 | 2024-03-08 | 台湾积体电路制造股份有限公司 | Semiconductor structure and semiconductor circuit |
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